Currently, with development of communications technologies, many data transmission networks use a multi-protocol label switching transport profile (MPLS-TP) technology.
One of the main functions of the MPLS-TP technology is keeping an unobstructed data transmission channel for carrying a network service. A channel protection switching mechanism in the MPLS-TP technology is basically that during data exchange between a source provider edge (PE) router and a sink PE router (generally, a source PE router is referred to as a source PE for short, and a sink PE router is referred to as a sink PE for short), two transmission channels, that is, a working channel and a protection channel, are often provided between the source PE and the sink PE. In a default state, the working channel is preferentially used for data exchange between the source PE and the sink PE. The source PE and the sink PE periodically send continuity check messages (CCMs) to each other, so as to determine whether a consecutive packet loss or a bit error occurs on the working channel. If a consecutive packet loss or a bit error occurs on the working channel, a channel used by the source PE and the sink PE is switched from the working channel to the protection channel.
However, in multiple complex service scenarios, factors affecting a network service are not limited to a consecutive packet loss or a bit error, and many other factors, for example, a transmission delay, cause a working channel to fail to be switched in time. However, according to current reception of a CCM, it is difficult to determine whether a relatively great delay exists in data transmission. Therefore, when multiple factors affect a network service, in a current channel protection switching mechanism, it is difficult to trigger in time switching of a working channel, and a channel with a relatively low transmission capability is still used to carry the network service, thereby reducing quality of the network service in a complex service scenario.